package com.imooc.service;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

@Component
@Slf4j
public class RedisLock {

    @Autowired
    private StringRedisTemplate redisTemplate;

    public boolean lock(String key,String value){
        if(redisTemplate.opsForValue().setIfAbsent(key, value)){
            return true;
        }
        String currentValue=redisTemplate.opsForValue().get(key);
        //如果锁过期
        if(!StringUtils.isEmpty(currentValue)&&Long.parseLong(currentValue)<System.currentTimeMillis()){

            //如果再有两个线程进来，获取上一个锁的的时间，getAndSet(key, value)只允许一个线程执行
            String oldValue=redisTemplate.opsForValue().getAndSet(key, value);
            if(!StringUtils.isEmpty(oldValue)&&oldValue.equals(currentValue)){
                return true;
            }
        }
        return false;
    }


    //解锁
    public void unlock(String key,String value){
        try{
            String currentValue=redisTemplate.opsForValue().get(key);
            if(!StringUtils.isEmpty(currentValue)&&currentValue.equals(value)){
                redisTemplate.opsForValue().getOperations().delete(key);
            }
        }catch (Exception e){
            log.error("【redis分布式锁】解锁异常，e={}",e);
        }
    }
}
